The grading operations which can be carried out with a motor grader are diverse. The grader, for example can be employed to cut down and level a slope to provide a generally flat tract. It can be used to cut a road along a desired course or it can be used for such a simple task as transporting material from an accumulated stock from one location to another. This versatility of the motor grader stems from the construction thereof which allows a wide three-dimensional positioning of the grading plow. The plow, carried on a drawbar structure, can be rotated 360 degrees in a horizontal plane, it can be tilted forwardly or rearwardly relative to a horizontal plane (grade) and can along with the framing on which it is mounted, be tilted (relative to said plane) to the left and to the right to dispose the plow at an angle to the horizontal. Further, the plow can be translated or slid relative to its mounting.
There are however certain limitations in the use of a motor grader fitted with known types of plows. For example, in cutting a road it is not possible to cut or grade the road surface and downwardly inclining run-off surfaces commonly required at each of the road sides in the same grading pass. Thus, the grader must following a road , be returned to a starting point, the plow angled to correspond to a run-off cut disposition and then driven forwardly in a new cutting pass to grade the run-off. Another limitation is encountered where grading in multiple passes over an expansive area is carried out. In such operations, the plow usually will be angled to the right or left of the long axis of the grader. As the grader makes cutting passes removed grade material travels from the toe end to the heel of the plow and substantial quantity of material passes off at the heel leaving a windrow thereof along the cutting pass margin. This windrow must then be carried forward in the next pass but the windrow spillage process repeats itself. Thus extra passes of the grader must be made if ultimately all cut material is to be removed from initial to final tract locations.
In grading along a curb line where the plow will be angled to the right or left, spillover of material at the toe end of the plow to the rear side of the plow can occur as a cascading deposit onto the curbing frame requiring that extra labor be used to clear debris from the frame. Also, a conventional plow has only limited movement possibility when grading the environs of manhole frames and sewer boxes adjacent curb lines necessitating unneeded and multiple grader movements in and around such structures.
In addition to the foregoing, the conventional plow cannot present a configuration thereof which can retain and carry forwardly any significant quantity of cut grade material plows which can be folded to define material holding space are known. For example, bulldozer and snow plow blades comprised of two equal length blade halves pivoted together can be angled about the pivot from a flat front face plow disposition to a V-configuration to form a retention space with the folded halves. However, such retention space has limited volume and such plow cannot be angled or tilted in any of the many other plow configurations commonly used and/or required in a motor grading operation.